DHCP - "Cannot get IP address of my own host"

[Owen_PG]

I'm runnng my newly built PC as a DHCP client of a Linux box.  The previous 
Linux client and any MS Windows clients worked fine "straight out of the 
box".  With the FreeBSD 5.1 - 10 client, if I enable it as a DHCP client then 
it doesn't seem to use the DNS caching slave that is on the DHCP server.  But 
all other clients can resolve URLs on the Internet.

If I log onto a virtual terminal I can use cvsup OK but if I start up KDE and 
use it in a KDE Konsole it comes back with:

mk1 root 510-->cd
~
mk1 root 511-->pwd
/root
~
mk1 root 512-->cvsup stable-supfile
Cannot get IP address of my own host -- is its hostname correct?
~
mk1 root 513--> 

I have left /etc/dhclient.conf blank.  If I replace the /etc/rc.conf file 
entry with a hard coded IP address everything works again.

Any ideas gratefully recieved,

Owen (Newbie to BSD)